Will it be possible to render out the Workbench viewports in Blender 2.8?
In Blender 2.80 the workbench engine can be used as an interactive viewport renderer, viewport rendering (to image or animation) or final render (image or animation.

Interactive Viewport

Workbench is used when the viewport is in Solid mode. 

Viewport Rendering

In the view menu there are two operations. One for Viewport Render Image and one for Viewport Render Animation it will use the same settings as your current viewport.

Workbench as render engine

In the Properties panel it is possible to set the render engine to Workbench. Now when you do a final rendering it will use the workbench engine.